1. Field of the Invention
This invention relates generally to fluid flow control devices, and more particularly to an adjustable flow regulating valve having an automatic gradually variable effective flow controlling orifice with the range of variation being manually adjustable.
2. Brief Description of the Prior Art
Conventional liquid beverage dispensing machines, such as coffee makers and soft drink machines, are typically connected to the water supply line of the building in which they reside. The water supply pressure will often vary due to other demands on the water supply either outside or inside of the building. Most dispensing machines of this type utilize a predetermined mixture of water and other ingredients such as coffee grounds or syrup concentrate to produce the final consumable product. Excessive variations in the water pressure adversely affects the quality of the beverage produced due to an incorrect water mixture.
Flow control valves are known which are intended to provide a controlled or regulated flow rate regardless of changes in the inlet pressure. In general, these valves are rather complex and are not easily installed or replaced in a fluid system. Valves of this type must be removed for cleaning or replacement due to the components becoming unworkable because of calcium and other mineral deposits. Some flow control valves are not easily adjustable. In some cases, minimal adjustment of the regulated flow rate can be achieved by adjusting the spring force on the control element. In most cases, however, when significant changes in the controlled flow rate are desired, the valve assembly must be replaced with one having the desired flow characteristics.
There are several patents which disclose flow control devices of various construction, but do not have the same structural or operational features of the present invention.
Bron, U.S. Pat. No. 4,428,397 and German Patent No. 2,748,055 disclose a flow rate control device comprising a housing with an elastic stretch-able membrane dividing the housing into two chambers with passageways therebetween. When exposed to a fluid pressure differential, the membrane will stretch between a position closer to the outlet port to restrict the flow or away from the outlet port to increase the flow rate.
Andresen, U.S. Pat. No. 3,419,038 discloses a flow controller comprising a housing with a flexible resilient diaphragm which is creased and supported on a wire member to allow flow through a central hole and around its rim. Excess pressure flattens the diaphragm to close off flow around its rim which then passes through the central hole.
Takahashi et al, U.S. Pat. No. 4,648,424 discloses a liquid flow rate controller comprising a casing with a sliding cup-shaped valve body having a hole at the upstream end which is urged upstream by a spring. Excess pressure moves the valve body downsteam onto a needle to restrict the flow. The distance between the needle and the valve body hole is adjustable.
Boyce, U.S. Pat. No. 4,669,495 discloses an adjustable flow regulating valve comprising a spool slidably mounted within a step bore in the valve body the spool carries a stem with a tapered end which moves in and out of an orifice in the spool to adjust the effective orifice size.
Segelhorst et al, U.S. Pat. No. 2,829,674 discloses an automatic fluid control device comprising a housing with several openings around a small tube running through the center which is surrounded by a flexible resilient plug having a central hole. When the pressure is not excessive, fluid flows through the openings, the central hole, and the tube. Excessive pressure flattens the plug around the tube to close off flow through the central hole allowing reduced flow primarily through the tube only.
Allen, U.S. Pat. No. 2,938,538 discloses a flow regulating valve wherein fluid flows through one or more fixed orifices in a cone disk spring defining one wall of a reference chamber, into a pressure chamber, then through a regulating orifice and out through a discharge port. A valve plunger on the cone disk coacts with the regulating orifice to control the orifice area and the fluid flow through the valve.
The present invention is distinguished over the prior art in general, and these patents in particular by an adjustable flow regulating valve having a flexible apertured diaphragm which coacts with a fixed conical needle to provide a gradually variable effective flow controlling orifice area to compensate for changes in a supply fluid pressure. As the supply fluid pressure changes, the aperture of the flexible diaphragm moves relative to the apex of the needle to reduce or increase the effective orifice area which determines the regulative flow rate. The position of the diaphragm aperture relative to the needle is manually adjustable by rotating an adjustment collar on the valve housing to vary the amount of movement of the diaphragm required to engage the aperture with the valve needle. The diaphragm may also be carried by a spring balanced inner sleeve which allows relative sliding movement between the flexible diaphragm and the needle. The amount of force required for engagement is determined by the strength of compression springs at each end of the sliding sleeve set by the adjustment collar. Varying the spring resistance varies the amount of pressure required to engage the tapered surface with the diaphragm aperture.